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我正在使用此脚本将帧转换为时间码。为什么我00:30:00:00在使用43156.8as 值时得到结果，但 00:29:59:23在传递与变量完全相同的值时？

function framesToTC($frames, $framerate) {
    $hours = floor( $frames / ( $framerate * 60 * 60 ) );
    $framesleft = $frames - ($hours * $framerate * 60 * 60);
    $minutes = floor( $framesleft / ( $framerate * 60 ) );
    $framesleft -= ( $minutes * $framerate * 60 );
    $seconds = floor( $framesleft / ( $framerate ) );
    $framesleft -= ( $seconds * $framerate );
    $tc = sprintf("%02d:%02d:%02d:%02d", $hours, $minutes, $seconds, $framesleft );
    return $tc;
}
$frames = 86400000/48000*23.976; //43156.8
echo framesToTC($frames, 23.976) . '<br />'; //00:29:59:23
echo framesToTC(43156.8, 23.976); //00:30:00:00
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1 回答 1

3

我爆炸了你的功能（当有疑问时打印出来，这是我的座右铭）

<?php

function framesToTC($frames, $framerate) {
    echo "\n".str_pad(" START ", 40, "=", STR_PAD_BOTH)."\n";
    echo "frames: {$frames}\n";
    echo "framerate: {$framerate}\n";

    $hours = floor( $frames / ( $framerate * 60 * 60 ) );
    echo "hours: {$hours}\n";

    $framesleft = $frames - ($hours * $framerate * 60 * 60);
    echo "framesleft: {$framesleft}\n";

    $x = $framesleft / ( $framerate * 60 );
    echo "x: {$x}\n";
    echo str_pad(" DEVIATION ", 40, "-", STR_PAD_BOTH)."\n";
    $minutes = floor( $x );
    echo "minute: {$minutes}\n";

    $framesleft -= ( $minutes * $framerate * 60 );
    echo "framesleft: {$framesleft}\n";

    $seconds = floor( $framesleft / ( $framerate ) );
    echo "seconds: {$seconds}\n";

    $framesleft -= ( $seconds * $framerate );
    echo "framesleft: {$framesleft}\n";

    $tc = sprintf("%02d:%02d:%02d:%02d", $hours, $minutes, $seconds, $framesleft );
    echo "tc: {$tc}\n";

    return $tc;
}

$frames = (86400000/48000*23.976); //43156.8
echo framesToTC($frames, 23.976) . "\n"; //00:29:59:23
echo framesToTC(43156.8, 23.976); //00:30:00:00

$frames = (86400000/48000*23.976); //43156.8
echo framesToTC($frames, 23.976) . "\n"; //00:29:59:23
echo framesToTC(43156.8, 23.976); //00:30:00:00

输出

================ START =================
frames: 43156.8
framerate: 23.976
hours: 0
framesleft: 43156.8
x: 30
-------------- DEVIATION ---------------
minute: 29
framesleft: 1438.56
seconds: 59
framesleft: 23.975999999998
tc: 00:29:59:23
00:29:59:23

================ START =================
frames: 43156.8
framerate: 23.976
hours: 0
framesleft: 43156.8
x: 30
-------------- DEVIATION ---------------
minute: 30
framesleft: 7.2759576141834E-12
seconds: 0
framesleft: 7.2759576141834E-12
tc: 00:30:00:00
00:30:00:00

看这里。 http://sandbox.onlinephpfunctions.com/code/918f5187e5dbab3f03812112a54f6b57754f5e7e

你可以通过四舍五入来“修复”我松散地使用这个词$framesleft。这里

echo "framesleft: {$framesleft}\n";

$framesleft = floor($framesleft);

$x = $framesleft / ( $framerate * 60 );

输出

================ START =================
frames: 43156.8
framerate: 23.976
hours: 0
framesleft: 43156.8
x: 29.999443888333
-------------- DEVIATION ---------------
minute: 29
framesleft: 1437.76
seconds: 59
framesleft: 23.176000000002
tc: 00:29:59:23
00:29:59:23

================ START =================
frames: 43156.8
framerate: 23.976
hours: 0
framesleft: 43156.8
x: 29.999443888333
-------------- DEVIATION ---------------
minute: 29
framesleft: 1437.76
seconds: 59
framesleft: 23.176000000002
tc: 00:29:59:23
00:29:59:23

在这里查看

http://sandbox.onlinephpfunctions.com/code/c78037e52d97ff50094cbc3b045309d155a302fa

我猜这与浮点精度有关，但这高于我的工资等级。但至少在这种情况下消除了偏差。您可能必须使用ceil，否则round我不知道正确答案应该是什么。我只是戳东西告诉它工作或一路中断......哈哈

于 2017-11-29T03:10:31.440 回答